686869 has 4 divisors (see below), whose sum is σ = 723040. Its totient is φ = 650700.

The previous prime is 686863. The next prime is 686879. The reversal of 686869 is 968686.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 686869 - 2⁵ = 686837 is a prime.

It is a super-2 number, since 2×686869² = 943578046322, which contains 22 as substring.

It is a Duffinian number.

686869 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18057 + ... + 18094.

It is an arithmetic number, because the mean of its divisors is an integer number (180760).

2⁶⁸⁶⁸⁶⁹ is an apocalyptic number.

It is an amenable number.

686869 is a deficient number, since it is larger than the sum of its proper divisors (36171).

686869 is a wasteful number, since it uses less digits than its factorization.

686869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36170.

The product of its digits is 124416, while the sum is 43.

The square root of 686869 is about 828.7756029228. The cubic root of 686869 is about 88.2316983023.

The spelling of 686869 in words is "six hundred eighty-six thousand, eight hundred sixty-nine".